1. Removed my Skype synergy account on Touchpad.
2. Removed Echo test contact from Skype on PC.
3. Added Echo test back as contact on PC and tested on PC just to make sure it was working.
4. Added Skype back as synergy account on Touchpad.
5. It took several minutes after signing into messaging app, but "Echo / Sound Test Service" finally showed up with a green dot (available) in both "Buddy" and "Favourite" sections where I could send a message (which would reset audio problems).